Neutron Measurement System and Method Based on Nanocoated Pixel Sensor

Abstract

A neutron measurement system and method based on a nano-coated pixel sensor, relating to the field of neutron measurement technology. The neutron measurement system based on a nano-coated pixel sensor includes a detector; the detector includes an active pixel sensor; the photosensitive surface of the active pixel sensor is not encapsulated in glass, and the photosensitive surface of the active pixel sensor has a layered neutron conversion material. A neutron measurement method is applied to the neutron measurement system based on a nano-coated pixel sensor; the method is as follows: a neutron undergoes a nuclear reaction with a target element, and the generated alpha rays are incident on the photosensitive surface of the active pixel sensor, causing the active pixel sensor to generate a radiation response signal; the indirect measurement of neutrons is achieved by statistically analyzing the radiation response signal. The advantage of this invention is that by combining a specific neutron conversion material with an active pixel sensor, neutron detection is transformed into alpha particle detection, which is the strength of the active pixel sensor, significantly improving the detection efficiency of neutrons (especially thermal neutrons).

Description

Technical Field

[0001] This invention relates to the field of neutron measurement technology, and in particular to a neutron measurement system and method based on a nano-coated pixel sensor. Background Technology

[0002] Neutrons are uncharged elementary particles. Due to their magnetic moment and strong penetrability, there is a demand for neutron measurement in many fields, including nuclear energy (monitoring the neutron radiation dose received by personnel during the operation and maintenance of nuclear power plants to ensure personnel safety), medicine (accurately measuring the neutron dose around the treatment area in radiotherapy to ensure patient safety), and materials (non-destructively obtaining information such as the internal crystal phase, grain orientation and size, and residual stress of materials through neutron diffraction technology for mechanism research, processing optimization, and failure assessment of new materials and components).

[0003] In the field of neutron measurement, neutron detectors based on helium-3 as the working medium are widely used, as helium-3 neutron detectors have high sensitivity and efficiency. However, with the rapid development of neutron measurement technology, the supply of helium-3 resources is becoming increasingly scarce, causing the cost of helium-3 neutron detectors to gradually rise. Therefore, there is an urgent need to develop neutron detectors based on new neutron measurement materials.

[0004] As alternatives to helium-3 neutron detectors, neutron detectors based on novel scintillator materials and semiconductor materials have been developed. However, these neutron detectors often suffer from problems such as large size, high cost, or inability to simultaneously achieve high sensitivity and spatial resolution (i.e., distinguishing the direction of neutron sources). Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a neutron measurement system and method based on a nano-coated pixel sensor. It solves the problems of existing neutron detectors based on novel scintillator materials and semiconductor materials, such as large size, high cost, or inability to simultaneously achieve high sensitivity and spatial resolution.

[0006] The technical solution of the present invention is: a neutron measurement system based on a nano-coated pixel sensor, including a detector; the detector includes an active pixel sensor; the photosensitive surface of the active pixel sensor is not encapsulated with glass, and the photosensitive surface of the active pixel sensor is attached, pasted, or arranged in a layered manner opposite each other with a layered neutron conversion material, which is used to react with neutrons to generate alpha rays.

[0007] A further technical solution of the present invention is: the neutron conversion material is attached or disposed face-to-face on the photosensitive surface of the active pixel sensor, the neutron conversion material is a two-dimensional hexagonal boron nitride thin film with a thickness between 200 nm and 2 μm, the two-dimensional hexagonal boron nitride thin film is attached to the surface of a copper foil, and the boron element in the two-dimensional hexagonal boron nitride is... 10 B.

[0008] A further technical solution of the present invention is as follows: the processing of the active pixel sensor is as follows: a copper foil sheet with the same size and shape as the photosensitive surface of the active pixel sensor is prepared for later use; a two-dimensional hexagonal boron nitride thin film with a thickness between 200nm and 2um is first deposited on the surface of the copper foil sheet by chemical vapor deposition, thereby obtaining the neutron conversion material; then the two-dimensional hexagonal boron nitride thin film in the neutron conversion material is attached to or arranged opposite the photosensitive surface of the active pixel sensor that has been stripped of its glass encapsulation.

[0009] A further technical solution of the present invention is: a layer of slowing material for slowing fast neutrons into slow neutrons is attached to the surface of the copper foil that is not in contact with the two-dimensional hexagonal boron nitride, and the slowing material is paraffin wax.

[0010] A further technical solution of the present invention is: the neutron conversion material is attached to the photosensitive surface of the active pixel sensor, and the neutron conversion material is a lithium fluoride thin film with a thickness between 200 nm and 2 μm, wherein the lithium element in the lithium fluoride is... 6 Li.

[0011] A further technical solution of the present invention is as follows: the processing of the active pixel sensor is as follows: a lithium fluoride thin film with a thickness between 200nm and 2um is deposited on the photosensitive surface of the active pixel sensor after the glass encapsulation has been removed using vacuum thermal evaporation coating technology.

[0012] A further technical solution of the present invention is: a layer of moderator material, which is paraffin, is attached to the surface of the lithium fluoride film to slow down fast neutrons into slow neutrons.

[0013] A further technical solution of the present invention is: the neutron conversion material is attached or disposed face-to-face on the photosensitive surface of the active pixel sensor, the neutron conversion material is a boron carbide thin film with a thickness between 200 nm and 2 μm, the boron carbide thin film is attached to the surface of a copper foil, and the boron element in the boron carbide is... 10 B.

[0014] A further technical solution of the present invention is as follows: the processing of the active pixel sensor is as follows: a copper foil sheet with the same size and shape as the photosensitive surface of the active pixel sensor is prepared for later use; a boron carbide thin film with a thickness of 200nm to 2um is first deposited on the surface of the copper foil sheet by magnetron sputtering, thereby obtaining the neutron conversion material; then the boron carbide thin film in the neutron conversion material is attached to or arranged opposite the photosensitive surface of the active pixel sensor that has been stripped of its glass encapsulation.

[0015] A further technical solution of the present invention is: a layer of slowing material, namely paraffin, is attached to the surface of the copper foil that is not in contact with boron carbide to slow down fast neutrons.

[0016] The technical solution of the present invention is: a neutron measurement method, applied to the above-mentioned neutron measurement system based on a nano-coated pixel sensor;

[0017] The detector also includes a circuit board and a chip board; an active pixel sensor is mounted on the circuit board, the circuit board is communicatively connected to the chip board, and a SoC chip is mounted on the chip board. The chip board is used to output frame images containing radiation response signals; the neutron detection system based on the nano-coated pixel sensor also includes a PC; the PC is communicatively connected to the chip board, and the PC is used to adjust the parameters of the active pixel sensor, as well as to store and display frame images containing radiation response signals.

[0018] The method is as follows: When a neutron passes through a neutron conversion material, it undergoes a nuclear reaction with the target element, and the resulting alpha rays are incident on the photosensitive surface of the active pixel sensor, causing the active pixel sensor to generate a radiation response signal; the chip board receives the output data of the active pixel sensor through the SoC chip, processes it and converts it into a continuous frame image, and then transmits it to the PC. By statistically analyzing the radiation response signal, the indirect measurement of neutrons is achieved.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. It combines specific neutron conversion materials with active pixel sensors, transforming neutron detection into alpha particle detection, which is an area where active pixel sensors excel, thus significantly improving the detection efficiency of neutrons (especially thermal neutrons).

[0021] 2. Compared with existing neutron detectors based on novel scintillator materials and semiconductor materials, it has the advantages of small size, low manufacturing and usage costs, and high sensitivity and spatial resolution (by combining the orientation of the active pixel sensor and the concentrated area of ​​the radiation response signal on the frame image, the direction of the neutron source can be distinguished).

[0022] 3. Flexible Functional Configuration: Depending on the actual application requirements, the visible light detection capability of the active pixel sensor can be selectively retained (using lithium fluoride (LiF) coating, but with relatively weak neutron detection capability) or focused on stronger neutron detection capability (using two-dimensional hexagonal boron nitride (2D h-BN) or boron carbide (B4C) or... 10 B-type elemental coating (but can no longer be used for detecting visible light), enabling flexible configuration of functions.

[0023] 4. High system integration: The entire system is built on CMOS APS, which makes it easy to integrate with other electronic systems and facilitates the realization of miniaturized and portable neutron detection equipment.

[0024] The present invention will be further described below with reference to the figures and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the detector structure in Example 1;

[0026] Figure 2 This is a schematic diagram of the detector structure in Example 2.

[0027] Figure 3 This is a schematic diagram of the detector structure in Example 3;

[0028] Figure 4 This is a schematic diagram of the detector in Example 4.

[0029] Legend: Active pixel sensor 1; Boron nitride 21; Lithium fluoride 22; Boron carbide 23; 10 B element 24; copper foil 25.

[0030] Note: Example 3 specifies two placement methods: direct placement and facing each other with spacing. Figure 2 Only the arrangement of facing each other across the distance is shown in the image. Detailed Implementation Example 1

[0031] like Figure 1 As shown, a neutron measurement system based on a nano-coated pixel sensor includes a detector. The detector includes an active pixel sensor 1. The photosensitive surface of the active pixel sensor 1 is not encapsulated in glass, and a layered neutron conversion material is attached to the photosensitive surface of the active pixel sensor 1. The neutron conversion material is used to undergo a nuclear reaction with neutrons and generate alpha rays.

[0032] The neutron conversion material is either attached or disposed face-up on the photosensitive surface of the active pixel sensor 1. The neutron conversion material is a two-dimensional hexagonal boron nitride 21 thin film with a thickness between 200 nm and 2 μm. The two-dimensional hexagonal boron nitride 21 thin film is attached to the surface of the copper foil 25. The boron element in the two-dimensional hexagonal boron nitride 21 is... 10 B.

[0033] The processing procedure for the active pixel sensor is as follows: A copper foil 25 with the same size and shape as the photosensitive surface of the active pixel sensor 1 is prepared for later use; a two-dimensional hexagonal boron nitride 21 film with a thickness between 200 nm and 2 μm is first deposited on the surface of the copper foil 25 using chemical vapor deposition (the boron element in the two-dimensional hexagonal boron nitride 21 is...). 10 B), that is, the neutron conversion material is obtained; then the two-dimensional hexagonal boron nitride 21 film in the neutron conversion material is bonded to or arranged opposite each other with the photosensitive surface of the active pixel sensor 1, which has been stripped of its glass encapsulation.

[0034] When using a non-contact, face-to-face arrangement, the distance between the surface of the two-dimensional hexagonal boron nitride connected to the copper foil and the photosensitive surface of the active pixel sensor should be less than 2 mm. Regardless of whether a surface-mount or non-contact arrangement is used, an external fixing structure (support structure) is required to maintain the relative fixation of the active pixel sensor and the neutron conversion material.

[0035] Preferably, the surface of the copper foil 25 that is not in contact with the two-dimensional hexagonal boron nitride 21 is coated with a layer of moderating material to slow down fast neutrons into slow neutrons, in order to improve measurement efficiency. The moderating material is paraffin wax, and the thickness of the moderating material is selected according to the highest energy of the incident fast neutron. Example 2

[0036] like Figure 2 As shown, the only difference between this embodiment and Embodiment 1 is that the neutron conversion material is attached to the photosensitive surface of the active pixel sensor 1, and the neutron conversion material is a lithium fluoride 22 thin film with a thickness between 200 nm and 2 μm, wherein the lithium element in the lithium fluoride 22 is... 6 Li.

[0037] The processing procedure for the active pixel sensor is as follows: A lithium fluoride 22 film with a thickness between 200 nm and 2 μm is deposited on the photosensitive surface of the active pixel sensor 1, after the glass encapsulation has been removed, using vacuum thermal evaporation coating technology. (The lithium element in lithium fluoride is...) 6 Li).

[0038] Preferably, the surface of the lithium fluoride 22 thin film is coated with a moderating material for slowing down fast neutrons to improve measurement efficiency. The moderating material is paraffin wax, and the thickness of the moderating material is selected according to the highest energy of the incident fast neutron. Example 3

[0039] like Figure 3 As shown, the only difference between this embodiment and Embodiment 1 is that the neutron conversion material is either attached or disposed face-to-face on the photosensitive surface of the active pixel sensor 1. The neutron conversion material is a boron carbide 23 film with a thickness between 200 nm and 2 μm. The boron carbide 23 film is attached to the surface of the copper foil 25, and the boron element in the boron carbide 23 is... 10 B.

[0040] The processing procedure for the active pixel sensor is as follows: A copper foil 25 with the same size and shape as the photosensitive surface of the active pixel sensor is prepared for later use; firstly, a boron carbide 23 thin film with a thickness between 200 nm and 2 μm is deposited on the surface of the copper foil 25 using magnetron sputtering (the boron element in boron carbide 23 is...). 10B), that is, the neutron conversion material is obtained; then the boron carbide 23 film in the neutron conversion material is attached to or arranged opposite each other to the photosensitive surface of the active pixel sensor 1, which has been stripped of its glass encapsulation.

[0041] When using an air-to-face arrangement, the distance between the surface of the boron carbide sensor connected to the copper foil and the photosensitive surface of the active pixel sensor should be less than 2mm. Regardless of whether an adhesive or air-to-face arrangement is used, an external fixing structure (support structure) is required to maintain the relative fixation of the active pixel sensor and the neutron conversion material.

[0042] Preferably, the surface of the copper foil 25 that is not in contact with the boron carbide 23 is coated with a layer of moderating material for slowing fast neutrons into slow neutrons, the moderating material being paraffin wax. Example 4

[0043] like Figure 4 As shown, the only difference between this embodiment and Embodiment 1 is that the neutron conversion material is either attached or disposed face-to-face on the photosensitive surface of the active pixel sensor 1, and the neutron conversion material has a thickness between 200 nm and 2 μm. 10 B elemental 24 thin film, 10 A thin film of element B 24 is attached to the surface of copper foil 25.

[0044] The processing procedure for the active pixel sensor is as follows: Prepare a copper foil 25 with the same size and shape as the photosensitive surface of the active pixel sensor 1; first, deposit a layer with a thickness between 200 nm and 2 μm on the surface of the copper foil 25 using chemical vapor deposition. 10 A thin film of elemental B24 is obtained, thus yielding the neutron conversion material; then, the neutron conversion material contains... 10 The B elemental 24 film is either bonded to or positioned opposite the photosensitive surface of the active pixel sensor 1, which has had its glass encapsulation removed.

[0045] When using an open-plan, facing arrangement 10 The distance between the surface of element B connected to the copper foil and the photosensitive surface of the active pixel sensor should be less than 2 mm. Regardless of whether a fixed or air-mounted arrangement is used, the active pixel sensor and the neutron conversion material must be kept relatively fixed by an external fixing structure (support structure).

[0046] A neutron measurement method is provided, applied to the aforementioned neutron measurement system based on a nano-coated pixel sensor. The detector further includes a circuit board and a chip board; the active pixel sensor is mounted on the circuit board, which is communicatively connected to the chip board. A SoC chip is mounted on the chip board, which outputs frame images containing radiation response signals. The neutron detection system based on the nano-coated pixel sensor also includes a PC; the PC is communicatively connected to the chip board and is used to adjust the parameters of the active pixel sensor, as well as to store and display the frame images containing radiation response signals.

[0047] The method is as follows: When a neutron passes through a neutron conversion material, it undergoes a nuclear reaction with the target element, generating alpha rays that are highly sensitive to active pixel sensors. The alpha rays are incident on the photosensitive surface of the active pixel sensor, causing the active pixel sensor to generate a radiation response signal. The chip board receives the output data of the active pixel sensor through the SoC chip, processes it and converts it into continuous frame images, and then transmits it to the PC. By statistically analyzing the radiation response signal, the indirect measurement of neutrons is achieved.

[0048] Corresponding to Example 1: When the neutron conversion material is the two-dimensional hexagonal boron nitride (2D h-BN), the target element is 10 B; At this time, the neutron and 10 The nuclear reaction B occurs as follows: n+ 10 B → α+ 7 Li+ 2.792 MeV.

[0049] Corresponding to Example 2: When the ion conversion material is the lithium fluoride (LiF), the target element is 6 Li, at this time, the neutron and 6 The nuclear reaction of Li is as follows: n+ 6 Li→α+ 3 T+4.786MeV.

[0050] Corresponding to Example 3: When the neutron conversion material is the boron carbide (B4C), the target element is 10 B; At this time, the neutron and 10 The nuclear reaction B occurs as follows: n+ 10 B → α+ 7 Li+ 2.792 MeV.

[0051] Corresponding to the case of Example 4: when the neutron conversion material is the described 10 In elemental B, neutrons and 10 The nuclear reaction B occurs as follows: n+ 10 B → α+ 7 Li+ 2.792 MeV.

Claims

1. A neutron measurement system based on a nano-coated pixel sensor, characterized by: Includes a detector; the detector includes an active pixel sensor; the photosensitive surface of the active pixel sensor is not encapsulated with glass, and the photosensitive surface of the active pixel sensor is attached, pasted, or arranged in a layered manner opposite each other, the neutron conversion material is used to react with neutrons and generate alpha rays. The neutron conversion material is either attached or disposed face-up on the photosensitive surface of the active pixel sensor. The neutron conversion material is a two-dimensional hexagonal boron nitride thin film with a thickness between 200 nm and 2 μm. The two-dimensional hexagonal boron nitride thin film is attached to the surface of a copper foil. The boron element in the two-dimensional hexagonal boron nitride is... 10 B.

2. The neutron measurement system based on a nano-coated pixel sensor as described in claim 1, characterized in that: The processing procedure for the active pixel sensor is as follows: Prepare a copper foil sheet with the same size and shape as the photosensitive surface of the active pixel sensor; first, deposit a two-dimensional hexagonal boron nitride thin film with a thickness between 200nm and 2um on the surface of the copper foil sheet using chemical vapor deposition, thereby obtaining the neutron conversion material; then, attach or arrange the two-dimensional hexagonal boron nitride thin film in the neutron conversion material to the photosensitive surface of the active pixel sensor that has been stripped of its glass encapsulation.

3. The neutron measurement system based on a nano-coated pixel sensor as described in claim 2, characterized in that: The side of the copper foil that is not in contact with the two-dimensional hexagonal boron nitride is coated with a layer of moderator material, which is paraffin wax, to slow down fast neutrons into slow neutrons.

4. A neutron measurement system based on a nano-coated pixel sensor, characterized by: Includes a detector; the detector includes an active pixel sensor; the photosensitive surface of the active pixel sensor is not encapsulated with glass, and the photosensitive surface of the active pixel sensor is attached, pasted, or arranged in a layered manner opposite each other, the neutron conversion material is used to react with neutrons and generate alpha rays. The neutron conversion material is attached to the photosensitive surface of the active pixel sensor. The neutron conversion material is a lithium fluoride thin film with a thickness between 200 nm and 2 μm, and the lithium element in the lithium fluoride is... 6 Li.

5. The neutron measurement system based on a nano-coated pixel sensor as described in claim 4, characterized in that: The processing procedure for the active pixel sensor is as follows: A lithium fluoride thin film with a thickness between 200 nm and 2 μm is deposited on the photosensitive surface of the active pixel sensor, which has been stripped of its glass encapsulation, using vacuum thermal evaporation coating technology.

6. The neutron measurement system based on a nano-coated pixel sensor as described in claim 5, characterized in that: The surface of the lithium fluoride film is coated with a moderator material, which is paraffin, to slow down fast neutrons into slow neutrons.

7. A neutron measurement system based on a nano-coated pixel sensor, characterized by: Includes a detector; the detector includes an active pixel sensor; the photosensitive surface of the active pixel sensor is not encapsulated with glass, and the photosensitive surface of the active pixel sensor is attached, pasted, or arranged in a layered manner opposite each other, the neutron conversion material is used to react with neutrons and generate alpha rays. The neutron conversion material is either attached or disposed face-up on the photosensitive surface of the active pixel sensor. The neutron conversion material is a boron carbide thin film with a thickness between 200 nm and 2 μm, which is adhered to the surface of a copper foil. The boron element in the boron carbide is... 10 B.

8. The neutron measurement system based on a nano-coated pixel sensor as described in claim 7, characterized in that: The processing procedure for the active pixel sensor is as follows: Prepare a copper foil sheet with the same size and shape as the photosensitive surface of the active pixel sensor; first, deposit a boron carbide thin film with a thickness between 200nm and 2um on the surface of the copper foil sheet using magnetron sputtering, thereby obtaining the neutron conversion material; then, place or arrange the boron carbide thin film in the neutron conversion material directly opposite the photosensitive surface of the active pixel sensor, which has been stripped of its glass encapsulation.

9. The neutron measurement system based on a nano-coated pixel sensor as described in claim 8, characterized in that: The copper foil has a layer of slowing material attached to the side of the copper foil that is not in contact with boron carbide. The slowing material is paraffin.

10. A neutron measurement method, applied to the neutron measurement system based on a nano-coated pixel sensor as described in any one of claims 1-9; Its characteristics are: The detector also includes a circuit board and a chip board; an active pixel sensor is mounted on the circuit board, the circuit board is communicatively connected to the chip board, and a SoC chip is mounted on the chip board. The chip board is used to output frame images containing radiation response signals; the neutron detection system based on the nano-coated pixel sensor also includes a PC; the PC is communicatively connected to the chip board, and the PC is used to adjust the parameters of the active pixel sensor, as well as to store and display frame images containing radiation response signals. The method is as follows: When neutrons pass through neutron conversion material, they undergo nuclear reactions with the target element, and the resulting alpha rays are incident on the photosensitive surface of the active pixel sensor, causing the active pixel sensor to generate a radiation response signal. The chip board receives the output data of the active pixel sensor through the SoC chip, processes it and converts it into a series of frame images before transmitting it to the PC. By statistically analyzing the radiation response signal, the indirect measurement of neutrons is achieved.

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